Kirill Levchenko Ramamohan Paturi George Varghese On the difficulty of scalably detecting network attacks. 12-20 2004 conf/ccs/2004ccs ACM Conference on Computer and Communications Security http://doi.acm.org/10.1145/1030083.1030087 db/conf/ccs/ccs2004p.html#LevchenkoPV04